Update sharp to the latest version 🚀

[greenkeeper]

⚠️ Beta is ending on May 31st ⚠️
To continue using private repositories with Greenkeeper, you need to upgrade to a a paid plan.

Version 0.18.0 of sharp just got published.

Dependency	sharp
Current Version	0.17.3
Type	dependency

The version 0.18.0 is not covered by your current version range.

Without accepting this pull request your project will work just like it did before. There might be a bunch of new features, fixes and perf improvements that the maintainers worked on for you though.

I recommend you look into these changes and try to get onto the latest version of sharp.
Given that you have a decent test suite, a passing build is a strong indicator that you can take advantage of these changes by merging the proposed change into your project. Otherwise this branch is a great starting point for you to work on the update.

---

Commits

The new version differs by 28 commits.

• c879df3 Release v0.18.0
• 361ed98 Remove previously-deprecated output format 'option' functions
• d45f8ef Document the cache-free nature of metadata extraction #796
• d6a63d1 Docs refresh
• 4c6804e Add toFormat 'jpg' alias for 'jpeg' (#814)
• 99810c0 Add support for any rotation angle (#791)
• d15fb1a Docs: add link to TailorBrands-maintained libvips Dockerfiles (#813)
• 0a6d8b3 Ensure double to int cast introduced in 4d1a169 is static
• f78ffdb Upgrade to libvips v8.5.5
• b7b6fdb Update perf test contenders, add node-images
• e398b47 Prevent aliasing by using dynamic values for shrink(-on-load)
• 48f69f3 Upgrade libpng to v1.6.29
• 95850d7 Include pixel format depth when reading metadata
• c41d755 Ctor single arg: allow plain object, reject null/undefined
• 39a2178 Remove 'require' test as bufferutil now ships prebuilt

There are 28 commits in total.

See the full diff

Not sure how things should work exactly?

There is a collection of frequently asked questions and of course you may always ask my humans.

---

Your Greenkeeper Bot 🌴

[greenkeeper]

Version 0.18.1 just got published.

Update to this version instead 🚀

Commits

The new version differs by 5 commits.

• 9f20037 Release v0.18.1
• 2ebb090 Update Travis CI to Ubuntu 16.04
• 110fff3 Replace Node 7 with Node 8 in CI environment
• f42a1ce Recalculate residual after adjusting shrink #831
• 9e39a7f Correct shrink calc, regression introduced in e398b47 #831

See the full diff